Method of manufacturing magentic body

ABSTRACT

A method of manufacturing a magnetic body in which insulating magnetic powder particles are stacked and press-molded in a molding space, and wiring is formed on a surface of the insulating magnetic powder particles solidified by press molding is provided according to the present invention. The method includes: a first step S 10  of preparing a wiring plate which includes a sheet-shaped base plate and the wiring which is formed on the base plate and is removable from the base plate; a second step S 20  of stacking the insulating magnetic powder particles in the molding space, arranging the wiring plate on a surface of the insulating magnetic powder particles in a state that the wiring faces the surface of the insulating magnetic powder particles in an opposed manner, and press-molding the insulating magnetic powder particles and the wiring plate; and a third step S 30  of removing the base plate from the surface of the solidified insulating magnetic powder particles while leaving the wiring on the insulating magnetic powder particles in this order. According to the method of manufacturing a magnetic body of the present invention, it is possible to prevent the corrosion of the insulating magnetic powder particles thus realizing the manufacture of a highly reliable magnetic body.

RELATED APPLICATIONS

The present application is national phase of PCT/JP2008/061777 filed Jun. 27, 2008, and claims priority from Japanese Application No. 2007-168815 filed Jun. 27, 2007, the disclosures of which are hereby incorporated by reference herein in their entirety.

TECHNICAL FIELD

The present invention relates to a method of manufacturing a magnetic body, and more particularly to a method of manufacturing a magnetic body which has wiring on a front surface thereof.

BACKGROUND ART

The magnetic body manufactured by the method of manufacturing a magnetic body of the present invention is an element having an inductor and is also referred to as an inductor or a transformer . Such a magnetic body is formed in such a manner that insulating magnetic powder particles formed of iron particles each of which is covered with a thin insulating material layer are stacked in a molding space and, thereafter, the insulating magnetic powder particles are press-molded (see patent document 1 and patent document 2, for example).

Here, the insulating magnetic powder particles have insulating property and hence, the manufactured magnetic body also has insulating property. Accordingly, it is possible to directly form wiring with a desired pattern on a front surface of the magnetic body. Eventually, it is possible to mount electronic parts such as electronic elements, semiconductor elements and IC chips on the wiring.

Here, the wiring formed on the front surface of the magnetic body may be formed as follows. That is, firstly, for example, a copper foil is formed on the whole front surface of the magnetic body and, thereafter, the copper foil is etched thus forming the wiring with a desired pattern.

Patent document 1: JP-A-2007-13176 Patent document 2: JP-A-2006-283190

DISCLOSURE OF THE INVENTION Task to Be Solved By the Invention

However, in the above-mentioned conventional method of manufacturing a magnetic body, the insulating magnetic powder particles are vulnerable to an etchant and hence, the insulating magnetic powder particles are corroded when etching is applied to the copper foil thus giving rise to a drawback that the manufacture of a highly reliable magnetic body becomes difficult.

The present invention has been made to overcome the above-mentioned drawbacks, and it is an object of the present invention to provide a method of manufacturing a magnetic body which can manufacture a highly reliable magnetic body by preventing corrosion of insulating magnetic powder particles.

Means for Solving the Problems

(1) The method of manufacturing a magnetic body of the present invention is made for achieving the above-mentioned object. In a method of manufacturing a magnetic body in which insulating magnetic powder particles are stacked in a molding space and are press-molded, and wiring is formed on a surface of the insulating magnetic powder particles solidified by press molding, the method includes: a first step of preparing a wiring plate (it can be called a wiring substrate) which includes a sheet-shaped base plate (it can be called a sheet-shaped substrate) and the wiring which is formed on the base plate and is removable from the base plate; a second step of stacking the insulating magnetic powder particles in the molding space, arranging the wiring plate on a surface of the insulating magnetic powder particles in a state that the wiring faces the surface of the insulating magnetic powder particles in an opposed manner, and press-molding the insulating magnetic powder particles and the wiring plate; and a third step of removing the base plate from the surface of the solidified insulating magnetic powder particles while leaving the wiring on the surface of the solidified insulating magnetic powder particles in this order.

Due to such a constitution, according to the method of manufacturing a magnetic body of the present invention, by removing the base plate from the surface of the insulating magnetic powder particles while leaving the wiring on the insulating magnetic powder particles in the third step, it is possible to form the wiring with a desired pattern on the front surface of the magnetic body. As a result, different from a conventional method, it is no more necessary to apply etching to an electric conductive film formed on the front surface of the magnetic body and hence, it is possible to prevent the corrosion of the magnetic body thus enabling the manufacture of a highly reliable magnetic body.

(2) In the method of manufacturing a magnetic body of the present invention, the wiring plate may preferably be a wiring plate which is formed in such a manner that an electric conductive film is formed on the base plate and, thereafter, etching with a desired pattern is applied to the electric conductive film thus forming the wiring.

Due to such a method, it is possible to manufacture a highly-reliable and high-performance magnetic body using the wiring plate in which the wiring with a desired pattern is preliminarily formed on the base plate.

(3) In the method of manufacturing a magnetic body of the present invention, average surface roughness of the wiring may preferably be larger than an average particle size of the insulating magnetic powder particles.

Due to such a method, it is possible to arrange the insulating magnetic powder particles such that the insulating magnetic powder particles are filled in an uneven surface of the wiring during the second step. Accordingly, the degree of adhesiveness between the magnetic body and the wiring can be enhanced thus realizing the manufacture of the highly reliable magnetic body.

(4) In the method of manufacturing a magnetic body of the present invention, the wiring is preferably formed of a metal foil.

Due to such a method, it is possible to form wiring having low electric resistance and high mechanical strength thus realizing the manufacture of a high-performance and highly-reliable magnetic body.

(5) In the method of manufacturing a magnetic body of the present invention, the metal foil may preferably be a copper foil.

The copper foil has high ductility and hence, by adopting such a method, during the second step, it is possible not only to arrange the insulating magnetic powder particles such that the insulating magnetic powder particles are filled in an uneven surface of the wiring, but also to cause the plastic deformation of the copper foil such that the copper foil is filled in each gap formed between the insulating magnetic powder particles. Accordingly, the degree of adhesiveness between the magnetic body and the wiring can be further enhanced thus realizing the manufacture of the further highly-reliable magnetic body.

(6) In the method of manufacturing a magnetic body of the present invention, the base plate may preferably be made of a resin.

The resin has proper flexibility and hence, it is possible to enhance operability at the time of removing the base plate by adopting the above-mentioned method.

(7) In the method of manufacturing a magnetic body of the present invention, the second step may preferably include a pre-pressing step of stacking the insulating magnetic powder particles in the molding space, and applying pre-press molding to the insulating magnetic powder particles in such a stacked state for leveling the surface of the insulating magnetic powder particles, and a main pressing step of press-molding the insulating magnetic powder particles at a pressing pressure higher than a pressing pressure in the pre-press molding in a state where the wiring plate is arranged on a surface of the insulating magnetic powder particles such that the wiring faces the surface of the insulating magnetic powder particles in an opposed manner in this order.

Due to such a method, it is possible to arrange the wiring plate on the insulating magnetic powder particles after the surface of the insulating magnetic powder particles is leveled by the pre-pressing step and hence, it is possible to manufacture a high-performance magnetic body on which the wiring is formed with a uniform pressing force.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view for explaining a magnetic body 10 manufactured by a method of manufacturing a magnetic body according to an embodiment.

FIG. 2 is a flowchart for explaining the method of manufacturing a magnetic body according to the embodiment.

FIG. 3 is a view for explaining a first step S10 in the method of manufacturing a magnetic body according to the embodiment.

FIG. 4 is a view for explaining a second step S20 in the method of manufacturing a magnetic body according to the embodiment.

FIG. 5 is a view for explaining the second step S20 in the method of manufacturing a magnetic body according to the embodiment.

FIG. 6 is a view for explaining the second step S20 in the method of manufacturing a magnetic body according to the embodiment.

FIG. 7 is a view for explaining a third step S30 in the method of manufacturing a magnetic body according to the embodiment.

FIG. 8 is an enlarged cross-sectional view showing a surface state of wiring of a wiring plate used in a wiring peel-off strength test.

FIG. 9 is a view showing a result of a wiring peel-off strength test.

FIG. 10 is an enlarged cross-sectional view showing a state of an interface between a magnetic portion and the wiring of a specimen A.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments

Hereinafter, a method of manufacturing a magnetic body according to the present invention is explained in detail based on embodiments shown in drawings. In the explanation made hereinafter, with respect to drawings used for explaining the embodiments, identical constitutional elements are given the same symbols and their repeated explanation is omitted as much as possible.

1. Magnetic Body 10

FIG. 1 is a view for explaining a magnetic body 10 manufactured by a method of manufacturing a magnetic body of the embodiment.

The magnetic body 10 is a surface-mounting-type inductor which, as shown in FIG. 1, includes a magnetic portion 12 which is formed by press-molding insulating magnetic powder particles MP, wiring 13 with a desired pattern which is formed on a front surface of the magnetic portion 12, electrodes 14 which are formed on a back surface of the magnetic portion 12, and connection elements 16 which electrically connect the electrodes 14 and the wiring 13.

The magnetic portion 12 incorporates, as described later in conjunction with FIG. 7 (c), a coil 11 having a predetermined shape therein. The coil 11 is connected to the electrodes 14 thus constituting a portion of an electric circuit. Here, in FIG. 7 (c), the illustration of the electrodes 14 is omitted.

The wiring 13 is formed of an electric conductive film (a copper foil, for example) . The manner of forming the wiring 13 is described later.

The electrode 14 is formed using an electric conductive material (copper, for example). The electrodes 14 may be formed by working a plate-shaped member. Here, the electrodes 14 may also be formed together with the magnetic portion 12 such that electric conductive powder particles (copper powder particles, for example) is stacked at positions where the electrodes are formed at the time of stacking the insulating magnetic powder particles MP, for example, and the insulating magnetic powder particles MP and the electric conductive powder particles are compressed together.

The connection elements 16 are made of an electric conductive material (copper, for example), and are formed in a U-shape so as to clamp a front surface and a back surface of the magnetic portion 12. The wiring 13 and the electrodes 14 are electrically connected with each other via the connection elements 16.

Various kinds of electronic parts such as an IC chip 17, capacitors and resistors are mounted on the wiring 13, and the wiring 13 constitute an electric circuit together with these electronic parts.

The insulating magnetic powder particles MP are formed, as disclosed in patent document 2, in a following manner. That is, surfaces of electric conductive metal powder particles (iron particles, for example) are coated with a PHPS (perhydropolysilazane) solution and, then, the electric conductive metal powder particles are mixed with an organic binder solution and a coupling agent which is made of an epoxy-functional silane in a single form, an amino-functional silane in a single form or a mixture of these silanes and, thereafter, the solution is removed by evaporation. When the solution is removed, oxidation occurs so that a silica film is formed on the surfaces of the metal powder particles. Accordingly, the magnetic powder particles to which insulating property is imparted by the silica film are formed.

2. Method of Manufacturing Magnetic Body

FIG. 2 is a flowchart for explaining a method of manufacturing a magnetic body according to the embodiment.

FIG. 3 is a view for explaining a first step S10 in the method of manufacturing a magnetic body according to the embodiment. FIG. 3( a) to FIG. 3( f) are views showing respective steps of the first step S10.

FIG. 4 to FIG. 6 are views for explaining a second step S20 in the method of manufacturing a magnetic body according to the embodiment. FIG. 4 is a view showing molding dies 31 to 33 and respective raw materials (for the coil 11, the electrodes 14, insulating magnetic powder particles MP, and a wiring plate 4) used in the second step S20. FIG. 5( a) to FIG. 5( c) are views showing the respective steps of the second step S20. FIG. 6( a) to FIG. 6( f) are views showing the respective steps of the second step S20.

FIG. 7 is a view for explaining a third step S30 in the method of manufacturing a magnetic body according to the embodiment. FIG. 7( a) to FIG. 7( c) are views showing the respective steps of the third step S30. In FIG. 5 to FIG. 7, the illustration of the electrodes 14 is omitted.

The method of manufacturing a magnetic body according to the embodiment includes, as shown in FIG. 2, the first step S10, the second step S20, the third step S30 and the fourth step S40 in this order. Hereinafter, the method of manufacturing a magnetic body according to the embodiment is explained in detail in order of the first step S10, the second step S20, the third step S30 and the fourth step S40.

2-1. First Step S10

The first step S10 is a step where the wiring plate 4 which includes a sheet-shaped base plate 1 and the wiring 13 which is formed on the base plate 1 and is removable from the base plate 1 is prepared.

Firstly, as shown in FIG. 3( a), the sheet-shaped base plate 1 made of PET (polyethylene terephthalate), for example, is prepared as a base plate (step S11).

Next, as shown in FIG. 3( b), a copper foil 2 is formed on the whole front surface of the base plate 1 (step S12). Accordingly, compared to a case where wiring is formed by repeating screen printing plural times, it is unnecessary to perform aligning operations and overlaying operations and hence, the copper foil 2 can be relatively easily formed. Average surface roughness of the wiring is 6 μm, for example.

Next, as shown in FIG. 3 (c), a photo resist 3 is applied to the copper foil 2 by coating (step S13).

Subsequently, as shown in FIG. 3( d), photolithography is applied to the photo resist 3 thus patterning the photo resist 3 into a desired shape (step S14). FIG. 3( d) shows an example where the photo resist 3 is patterned as a positive resist.

Next, as shown in FIG. 3 (e), the copper foil 2 is etched using ferric chloride (step S15).

As a final step, as shown in FIG. 3 (f), the wiring 13 with a desired pattern is formed on the base plate 1 by removing the photo resist 3 (step S16). In this manner, the wiring plate 4 which includes the sheet-shaped base plate 1 and the wiring 13 which is formed on the base plate 1 and is removable from the base plate 1 is formed.

2-2. Second Step S20

The second step S20 is a step where the insulating magnetic powder particles MP are stacked in the molding space and, thereafter, the wiring plate 4 is arranged on a surface of the insulating magnetic powder particles MP in a state that the wiring 13 faces the surface of the insulating magnetic powder particles MP in an opposed manner, and the insulating magnetic powder particles MP and the wiring plate 4 are press-molded.

Firstly, as shown in FIG. 4, the coil 11 and the electrodes 14 are arranged in the molding space defined by the respective molding dies 31 to 33. Thereafter, as shown in FIG. 5( a) and FIG. 6( a) to FIG. 6( c), the insulating magnetic powder particles MP are stacked in the molding space in a state that the insulating magnetic powder particles MP cover the coil 11, and pre-press molding is applied to the insulating magnetic powder particles MP in such a stacked state for leveling the surface of the insulating magnetic powder particles MP (pre-pressing step, step S21). Pressing pressure in the pre-pressing molding is 0.01 GPa to 0.05 GPa, for example. An average particle size of insulating magnetic powder particles is 5 μm, for example.

The molding die 31 is configured to define an outer peripheral shape of the magnetic body 10 by compression from a front surface and a back surface of the magnetic body 10. The magnetic body 10 has a rectangular parallelepiped shape.

Next, as shown in FIG. 5( b) and FIG. 5( c) as well as FIG. 6( d) and FIG. 6( e), press molding is applied to the insulating magnetic powder particles MP at a pressing pressure higher than the pressing pressure in the pre-press molding in a state where the wiring plate 4 is arranged on a surface of the insulating magnetic powder particles MP such that the wiring 13 faces the surface of the insulating magnetic powder particles MP in an opposed manner (main pressing step, steps S22 and S23). The pressing pressure in the main-press molding is 0.65 GPa to 1.0 GPa, for example.

After completion of the second step S20, as shown in FIG. 6( f), a molded body 15 is taken out from the molding die 31. Due to such steps, it is possible to take out the molded body 15 in a state that the insulating magnetic powder particles MP are solidified, the wiring 13 is embedded into the front surface of the magnetic portion 12, and the electrodes 14 are embedded into the back surface of the magnetic portion 12 (see FIG. 1).

Thereafter, the molded body 15 is heated at a temperature of 120° C. to 180° C. for 20 minutes to 1 hour, and more preferably, at a temperature of 130° C. to 140° C. for 1 hour. Due to such heating, the magnetic portion 12 is hardened.

2-3. Third Step S30

The third step S30 is a step where the base plate 1 is removed from the surface of the solidified insulating magnetic powder particles MP while leaving the wiring 13 on the surface of the solidified insulating magnetic powder particles MP.

In the third step S30, as shown in FIG. 7( a) to FIG. 7( c), the base plate 1 is removed from the surface of the solidified insulating magnetic powder particles MP (molded body 15) while leaving the wiring 13 on the surface of the solidified insulating magnetic powder particles MP (steps S31 to S33).

2-4. Fourth Step S40

The fourth step S40 is a step where the connecting elements 16 are mounted on the magnetic portion 12, and electronic parts such as the IC chip 17, capacitors and resistors are mounted on the magnetic portion 12.

In the fourth step S40, the U-shaped connecting elements 16 are mounted on the magnetic portion 12 from a side-surface side of the magnetic portion 12 in such a manner that the U-shaped connecting elements 16 clamp a front surface and a back surface of the magnetic portion 12. Due to such a step, the electrodes 14 and the wiring 13 are electrically connected with each other by the connecting elements 16. Thereafter, electronic parts such as the IC chip 17, the capacitors and the resistors are mounted on the front surface of the magnetic portion 12. Due to such a step, the magnetic body 10 is completed.

3. Advantageous Effects Brought About By the Method of Manufacturing a Magnetic Body of This Embodiment

According to the method of manufacturing a magnetic body of this embodiment, by removing the base plate 1 from the surface of the insulating magnetic powder particles MP while leaving the wiring 13 on the surface of the insulating magnetic powder particles MP in the third step S30, it is possible to form the wiring 13 with a desired pattern on the front surface of the magnetic body 10. As a result, different from a related art, it is no more necessary to apply etching to an electric conductive film formed on the front surface of the magnetic body and hence, it is possible to prevent the corrosion of the insulating magnetic powder particles thus enabling the manufacture of a highly reliable magnetic body.

Further, according to the method of manufacturing a magnetic body of this embodiment, the magnetic body is manufactured using the wiring plate in which the wiring with a desired pattern is preliminarily formed on the base plate and hence, it is possible to manufacture a highly-reliable and high-performance magnetic body

Further, according to the method of manufacturing a magnetic body of this embodiment, the average surface roughness of the wiring 13 is set larger than the average particle size of the insulating magnetic powder particles MP and hence, it is possible to arrange the insulating magnetic powder particles MP such that the insulating magnetic powder particles MP are filled in an uneven surface of the wiring during the second step S20. Accordingly, the degree of adhesiveness between the magnetic body 10 (magnetic portion 12) and the wiring 13 can be enhanced thus realizing the manufacture of the highly reliable magnetic body.

In the method of manufacturing a magnetic body of this embodiment, the wiring 13 is formed of a metal foil (a copper foil) and hence, it is possible to form wiring having low electric resistance and high mechanical strength thus realizing the manufacture of a high-performance and highly-reliable magnetic body.

In the method of manufacturing a magnetic body of this embodiment, the metal foil is the copper foil 2 having high ductility and hence, during the second step S20, it is possible not only to arrange the insulating magnetic powder particles MP such that the insulating magnetic powder particles MP are filled in an uneven surface of the wiring 13, but also to cause the plastic deformation of the copper foil 2 such that the copper foil 2 is filled in each gap formed between the insulating magnetic powder particles MP. Accordingly, the degree of adhesiveness between the magnetic body 10 (magnetic portion 12) and the wiring 13 can be further enhanced thus realizing the manufacture of the further highly-reliable magnetic body.

Further, according to the method of manufacturing a magnetic body of this embodiment, the base plate 1 is made of a resin having proper flexibility and hence, it is possible to enhance operability at the time of removing the base plate 1.

Further, according to the method of manufacturing a magnetic body of this embodiment, it is possible to arrange the wiring plate 4 on the insulating magnetic powder particles MP (magnetic portion 12) after the surface of the insulating magnetic powder particles MP is leveled by the pre-pressing step and hence, it is possible to manufacture a high-performance magnetic body on which the wiring 13 is formed with a uniform pressing force.

Further, according to the method of manufacturing a magnetic body of this embodiment, a thickness of the copper foil 2 formed on the base plate 1 can be easily changed by a known method and hence, the wiring 13 having a desired thickness size can be easily formed on the front surface of the magnetic body 10 (magnetic portion 12).

Still further, in a conventional manufacturing method in which wiring is formed by a printing method, it is necessary to repeat screen printing plural times for forming wiring having a large thickness. To the contrary, according to the method of manufacturing a magnetic body of this embodiment, it is possible to easily increase a thickness of the copper foil 2 formed on the base plate 1 using a conventionally known method.

Test Example

Next, to clarify the relationship between the average surface roughness of the wiring and the degree of adhesiveness of the wiring, a wiring peel-off strength test (peeling strength test) is carried out.

FIG. 8 is an enlarged cross-sectional view showing a surface state of the wiring of the wiring plate used in the wiring peel-off strength test. FIG. 8( a) is an enlarged cross-sectional view showing the surface state of the wiring of the wiring plate used as a specimen A, and FIG. 8( b) is an enlarged cross-sectional view showing the surface state of the wiring of the wiring plate used as a specimen B.

1. Preparation of Specimens

Magnetic bodies are formed using a method substantially equal to the first step S10 to the third step S30 in the method of manufacturing a magnetic body according to the embodiment. The magnetic body has a longitudinal size of 10 mm, a lateral size of 10 mm and a height of 2 mm. Further, the wiring has a width of 3 mm and a thickness of 75 μm. As the insulating magnetic powder particles MP, insulating magnetic powder particles made of iron particles whose surfaces are coated with a silica film are used. An average particle size of the insulating magnetic powder particles MP is 5 μm.

1-1. Specimen A

The magnetic body is prepared using a wiring plate which is formed by applying a copper foil having average surface roughness Ra of 6 μm to a base plate as wiring (see FIG. 8( a)), and the magnetic body is used as the specimen A.

1-2. Specimen B

The magnetic body is prepared using a wiring plate which is formed by applying a copper foil having average surface roughness Ra of 2 μm to a base plate as wiring (see FIG. 8( b)), and the magnetic body is used as the specimen B.

2. Peel-off Strength Test

In the peel-off strength test, a tensile strength necessary for peeling off the wiring from the magnetic portion by pulling the wiring upward at a peel-off speed of 1 mm per minute is measured.

FIG. 9 is a view showing a result of the wiring peel-off strength test.

As shown in FIG. 9, it is confirmed that both the specimen A and the specimen B can acquire peel-off strength of 0.15 KN/m or more thus acquiring the practically sufficient degree of adhesiveness. It is confirmed that out of these specimens A and B, the specimen A can acquire peel-off strength of 0.5 KN/m thus acquiring particularly the excellent degree of adhesiveness.

FIG. 10 is an enlarged cross-sectional view showing a state of an interface between the magnetic portion and the wiring in the specimen A.

As can be clearly understood from FIG. 10, in the specimen A, the insulating magnetic powder particles are arranged to be filled in the uneven surface of the wiring.

Further, as can be also clearly understood from FIG. 10, in the specimen A, a copper foil is plastically deformed to be filled in gaps each of which is formed between the insulating magnetic powder particles.

Although the method of manufacturing the magnetic body of the present invention has been explained heretofore based on the above-mentioned embodiment, the present invention is not limited to the above-mentioned embodiment, and the present invention can be carried out in various modes without departing from the gist of the present invention. 

1. A method of manufacturing a magnetic body in which insulating magnetic powder particles are stacked in a molding space and are press-molded, and wiring is formed on a surface of the insulating magnetic powder particles solidified by press molding, the method comprising: a first step of preparing a wiring plate which includes a sheet-shaped base plate and the wiring which is formed on the base plate and is removable from the base plate; a second step of stacking the insulating magnetic powder particles in the molding space, arranging the wiring plate on a surface of the insulating magnetic powder particles in a state that the wiring faces the surface of the insulating magnetic powder particles in an opposed manner, and press-molding the insulating magnetic powder particles and the wiring plate; and a third step of removing the base plate from the surface of the solidified insulating magnetic powder particles while leaving the wiring on the surface of the solidified insulating magnetic powder particles in this order.
 2. A method of manufacturing a magnetic body according to claim 1, wherein the wiring plate is a wiring plate which is formed in such a manner that an electric conductive film is formed on the base plate, and etching with a desired pattern is applied to the electric conductive film thus forming the wiring.
 3. A method of manufacturing a magnetic body according to claim 1, wherein average surface roughness of the wiring is larger than an average particle size of the insulating magnetic powder particles.
 4. A method of manufacturing a magnetic body according claim 1, wherein the wiring is formed of a metal foil.
 5. A method of manufacturing a magnetic body according to claim 4, wherein the metal foil is a copper foil.
 6. A method of manufacturing a magnetic body according to claim 1, wherein the base plate is made of a resin.
 7. A method of manufacturing a magnetic body according to claim 1, wherein the second step includes: a pre-pressing step of stacking the insulating magnetic powder particles in the molding space, and applying pre-press molding to the insulating magnetic powder particles in such a stacked state for leveling the surface of the insulating magnetic powder particles; and a main pressing step of press-molding the insulating magnetic powder particles at a pressing pressure higher than a pressing pressure in the pre-press molding in a state where the wiring plate is arranged on a surface of the insulating magnetic powder particles such that the wiring faces the surface of the insulating magnetic powder particles in an opposed manner in this order. 